Mating and Breeding
Male and female stoats come together just once a year, during the spring or summer, to mate. Polygynous in their breeding habits, males leave their territories and go in search of several females. Once mated, the female delays implanting the fertilised egg for 9-10 months until the following spring. This is so she gives birth at the same time every year. When finally pregnant, she gives birth after four weeks to a litter of between six and 13 young, known as kits. Because several males may have mated with a single female, the litters are often of mixed paternity. The offspring of two or three different males can be found in the same nest. The young are born in April or May, almost naked, deaf and blind. Initially, they are fed solely on milk by the female. Their eyes open after two to three weeks. After four or five weeks, she will start to bring them solid food, though she may continue to give them milk for the following few weeks. During this period a male stoat will often come and impregnate all the female kits while they are still in the nest, and even blind and naked. Like their own mother, they will delay implanting the egg until the following year. By the age of seven or eight weeks, the young have grown their first coat of fur. Now they start to hunt with their mother. By 11-12 weeks old they are finally able to hunt by themselves. Females reach their full size at approximately six months; males do not do so until they are one year old. Stoats are generally fairly silent animals, but sometimes make a trilling sound before mating, or hiss or shriek when they are nervous or angry. The kits are usually more vocal, especially when playing, when they will chirp excitedly. They can live for five, and in exceptional cases as long as eight, years. However, most stoats only survive for one or two years, because of predation or shortage of food.